VMware vSphere 7 Foundations 3.3 - vSphere 7 Storage - vSphere Storage Multipathing

Описание: When we have multiple paths to the storage, we need to decide which path(s) to use. After this lecture, you'll be able to configure the vSphere Native Multipath Plugin (NMP) and its associated Path Selection Plugins (PSPs) to optimise your storage access.

Glossary for Module 3

SAN
Storage Area Network - a common approach to shared storage for servers and virtualisation hosts.

Host Bus Adapter (HBA)
An adapter in a server or host used to connect it to a SAN. In iSCSI, this can be a network adapter with hardware iSCSI support or it can be a software adapter. In FibreChannel, this is a dedicated FibreChannel HBA.

iSCSI
Protocol for Remote Block Storage over a normal IP network. Used to connect Servers and Hosts to shared storage systems, most common in smaller deployments

FibreChannel (FC)
A Layer 2 protocol designed specifically for connections to a SAN. Uses fibre optic cables to connect the SAN and Servers/Hosts, typically via a FibreChannel Switch

FibreChannel Arbitrated Loop (FC-AL)
Name given to a FibreChannel design that uses fibre optic cables to connect servers/hosts to a SAN directly, without using a FibreChannel Switch

Multipathing
Name given to storage configurations where the servers or hosts have multiple routes to the storage - for example, multiple HBAs in the host.

Native Multipathing Plugin
vSphere component responsible for Multipathing

Path Selection Plugin (PSP)
Plugin to the vSphere Native Multipathing Plugin that dictates how vSphere selects the path it will use for IO

Asymmetric Logical Unit Access (ALUA)
Used to describe a SAN design where there are 2 or more controllers and each controller is responsible for a different set of disks, but can take over for each other in the event of a hardware failure.

VMFS
VMware Proprietary File System - used for Datastores

Datastore
A vSphere object created on given storage, formatted using VMFS. Similar to a partition/volume in Windows

Thin Provisioning
A method for provisioning VM storage where only the space actually consumed within the VM is actually allocated on the storage. Can allow for more efficient storage consumption, but if storage is over-allocated and consumption reaches the capacity of the disk, the VMs will be suspended.

Raw Device Mapping
A method of storage which maps a Virtual Machine directly to a storage device. Has very specific use cases, such as Windows Failover Clustering.https://docs.vmware.com/en/VMware-vSp...

Virtual Disk
A disk in a Virtual Machine, usually backed by a VMDK stored on a DataStore.

VMDK
File format for storing a Virtual Disk on a Datastore

Module Summary
Storage is a very important building block in any virtualisation platform, so expect questions about storage in an exam. In particular, pay attention to “Configure iSCSI for a Production Environment”, as this is a likely exam topic. Also, remember that vSphere supports NFS v3 and v4.1.

Further Reading
https://docs.vmware.com/en/VMware-vSp...
https://docs.vmware.com/en/VMware-vSp...

Module 3 Playlist
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